1) Field of the Invention:
The present invention relates generally to agricultural implements such as field cultivators and chisel plows, and more specifically to structure for controlling the operating depth of such implements.
2) Related Art:
Single point depth control structures are widely used to control the working depth of an implement. A valve which controls the lift cylinders is actuated by a plunger mounted on a tube and bracket arrangement and controlled by rockshaft rotation. The movement of the plunger is highly susceptible to looseness in the various connections and joints. Unacceptable variations in implement working depth often result from inaccuracies and nonrepeatability introduced the looseness.
Other types devices are available to limit retraction of a cylinder to set working depth, including donut-shaped spacers placed over the cylinder rod or cylinder-mounted valves. However, most of these devices suffer from one or more disadvantages, such as inaccessibility and limited adjustment capability.